Perhaps you should try some spelling variations:
passiver » passive, passively, passiert
passiven » passive, passion
passivieren » passivierende, passivierung, passieren
passivierender » passivierendeder, passivierungder, passierender, passivierende, aktivierender

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: ((passiver OR (passiven OR passivieren)) OR passivierender).
• Adding a wildcard symbol may retrieve word variants: ((passiver or (passiven or passivieren)) or passivierender)*.